1. Field of the Invention
The present invention relates to a method and an apparatus for inspecting rough idling of a multiple-cylinder engine in a bench test after assembling of the engine.
2. Description of the Prior Art
In a general bench test, an assembled multiple-cylinder engine is driven under load at a certain period of time and subjected to an exhaust gas test on a test bench. However, since there has been no apparatus for inspecting the condition of engine revolution, the condition has been inspected only by human sense. Consequently, it has been impossible to correctly find in a short inspection time uneveness of revolution which is remarkably shown at a low speed, leading to problems after appliance of the engine to a vehicle such as abnormal vibration of the vehicle body during idling.
Further, it is difficult to find a cylinder getting out of order because of slightly bad conditions of some parts of the engine, and even in case the bad-conditioned parts can be easily repaired, it takes time to locate the positions thereof.
Still further, even when the engine is found to be in a bad condition, it is difficult to find the cause therefor. In this case, though in fact the engine can pass the bench test by replacement of a part of the cylinders such as an ignition plug or repair of an uncomplicated defective portion, the engine is returned to the factory as a failed one, leading to lowering of productivity and uneveness of engine performance.